With considerable attention being given alternate forms of energy, the efficient use of wind power and the capturing of increased energy from the winds has recieved much consideration. However, it has generally been known that the chances of obtaining increased energy from the winds is very slim. Due to the normally low Reynolds numbers of the prevailing ambient wind flows, it is difficult to extract more than 55% of the energy from the winds.
One attempt to harness increased wind energy power is disclosed in U.S. Pat. No. 4,070,131 wherein atmospheric wind is admitted tangentially into a vertical structure downstream of the wind turbine which produces a vortex flow and corresponding low pressure core tending to induce air flow across the horizontal turbine.
U.S. Pat. No. 4,031,405 discloses a horizontal turbine having a shroud which adjusts to the direction of wind to enhance the wind affects against the turbine.
Other attempts have been proposed for directing the wind and increasing its effects against a turbine blade including the provision of a turbine having variable pitch blades whereby the angle of attack is varied to compensate for the changes in wind directions.